1 /* $NetBSD: drm_framebuffer.h,v 1.2 2021/12/18 23:45:46 riastradh Exp $ */
2
3 /*
4 * Copyright (c) 2016 Intel Corporation
5 *
6 * Permission to use, copy, modify, distribute, and sell this software and its
7 * documentation for any purpose is hereby granted without fee, provided that
8 * the above copyright notice appear in all copies and that both that copyright
9 * notice and this permission notice appear in supporting documentation, and
10 * that the name of the copyright holders not be used in advertising or
11 * publicity pertaining to distribution of the software without specific,
12 * written prior permission. The copyright holders make no representations
13 * about the suitability of this software for any purpose. It is provided "as
14 * is" without express or implied warranty.
15 *
16 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
17 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
18 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
19 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
20 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
21 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
22 * OF THIS SOFTWARE.
23 */
24
25 #ifndef __DRM_FRAMEBUFFER_H__
26 #define __DRM_FRAMEBUFFER_H__
27
28 #include <linux/ctype.h>
29 #include <linux/list.h>
30 #include <linux/sched.h>
31
32 #include <drm/drm_mode_object.h>
33
34 struct drm_clip_rect;
35 struct drm_device;
36 struct drm_file;
37 struct drm_format_info;
38 struct drm_framebuffer;
39 struct drm_gem_object;
40
41 /**
42 * struct drm_framebuffer_funcs - framebuffer hooks
43 */
44 struct drm_framebuffer_funcs {
45 /**
46 * @destroy:
47 *
48 * Clean up framebuffer resources, specifically also unreference the
49 * backing storage. The core guarantees to call this function for every
50 * framebuffer successfully created by calling
51 * &drm_mode_config_funcs.fb_create. Drivers must also call
52 * drm_framebuffer_cleanup() to release DRM core resources for this
53 * framebuffer.
54 */
55 void (*destroy)(struct drm_framebuffer *framebuffer);
56
57 /**
58 * @create_handle:
59 *
60 * Create a buffer handle in the driver-specific buffer manager (either
61 * GEM or TTM) valid for the passed-in &struct drm_file. This is used by
62 * the core to implement the GETFB IOCTL, which returns (for
63 * sufficiently priviledged user) also a native buffer handle. This can
64 * be used for seamless transitions between modesetting clients by
65 * copying the current screen contents to a private buffer and blending
66 * between that and the new contents.
67 *
68 * GEM based drivers should call drm_gem_handle_create() to create the
69 * handle.
70 *
71 * RETURNS:
72 *
73 * 0 on success or a negative error code on failure.
74 */
75 int (*create_handle)(struct drm_framebuffer *fb,
76 struct drm_file *file_priv,
77 unsigned int *handle);
78 /**
79 * @dirty:
80 *
81 * Optional callback for the dirty fb IOCTL.
82 *
83 * Userspace can notify the driver via this callback that an area of the
84 * framebuffer has changed and should be flushed to the display
85 * hardware. This can also be used internally, e.g. by the fbdev
86 * emulation, though that's not the case currently.
87 *
88 * See documentation in drm_mode.h for the struct drm_mode_fb_dirty_cmd
89 * for more information as all the semantics and arguments have a one to
90 * one mapping on this function.
91 *
92 * Atomic drivers should use drm_atomic_helper_dirtyfb() to implement
93 * this hook.
94 *
95 * RETURNS:
96 *
97 * 0 on success or a negative error code on failure.
98 */
99 int (*dirty)(struct drm_framebuffer *framebuffer,
100 struct drm_file *file_priv, unsigned flags,
101 unsigned color, struct drm_clip_rect *clips,
102 unsigned num_clips);
103 };
104
105 /**
106 * struct drm_framebuffer - frame buffer object
107 *
108 * Note that the fb is refcounted for the benefit of driver internals,
109 * for example some hw, disabling a CRTC/plane is asynchronous, and
110 * scanout does not actually complete until the next vblank. So some
111 * cleanup (like releasing the reference(s) on the backing GEM bo(s))
112 * should be deferred. In cases like this, the driver would like to
113 * hold a ref to the fb even though it has already been removed from
114 * userspace perspective. See drm_framebuffer_get() and
115 * drm_framebuffer_put().
116 *
117 * The refcount is stored inside the mode object @base.
118 */
119 struct drm_framebuffer {
120 /**
121 * @dev: DRM device this framebuffer belongs to
122 */
123 struct drm_device *dev;
124 /**
125 * @head: Place on the &drm_mode_config.fb_list, access protected by
126 * &drm_mode_config.fb_lock.
127 */
128 struct list_head head;
129
130 /**
131 * @base: base modeset object structure, contains the reference count.
132 */
133 struct drm_mode_object base;
134
135 /**
136 * @comm: Name of the process allocating the fb, used for fb dumping.
137 */
138 char comm[TASK_COMM_LEN];
139
140 /**
141 * @format: framebuffer format information
142 */
143 const struct drm_format_info *format;
144 /**
145 * @funcs: framebuffer vfunc table
146 */
147 const struct drm_framebuffer_funcs *funcs;
148 /**
149 * @pitches: Line stride per buffer. For userspace created object this
150 * is copied from drm_mode_fb_cmd2.
151 */
152 unsigned int pitches[4];
153 /**
154 * @offsets: Offset from buffer start to the actual pixel data in bytes,
155 * per buffer. For userspace created object this is copied from
156 * drm_mode_fb_cmd2.
157 *
158 * Note that this is a linear offset and does not take into account
159 * tiling or buffer laytou per @modifier. It meant to be used when the
160 * actual pixel data for this framebuffer plane starts at an offset,
161 * e.g. when multiple planes are allocated within the same backing
162 * storage buffer object. For tiled layouts this generally means it
163 * @offsets must at least be tile-size aligned, but hardware often has
164 * stricter requirements.
165 *
166 * This should not be used to specifiy x/y pixel offsets into the buffer
167 * data (even for linear buffers). Specifying an x/y pixel offset is
168 * instead done through the source rectangle in &struct drm_plane_state.
169 */
170 unsigned int offsets[4];
171 /**
172 * @modifier: Data layout modifier. This is used to describe
173 * tiling, or also special layouts (like compression) of auxiliary
174 * buffers. For userspace created object this is copied from
175 * drm_mode_fb_cmd2.
176 */
177 uint64_t modifier;
178 /**
179 * @width: Logical width of the visible area of the framebuffer, in
180 * pixels.
181 */
182 unsigned int width;
183 /**
184 * @height: Logical height of the visible area of the framebuffer, in
185 * pixels.
186 */
187 unsigned int height;
188 /**
189 * @flags: Framebuffer flags like DRM_MODE_FB_INTERLACED or
190 * DRM_MODE_FB_MODIFIERS.
191 */
192 int flags;
193 /**
194 * @hot_x: X coordinate of the cursor hotspot. Used by the legacy cursor
195 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
196 * universal plane.
197 */
198 int hot_x;
199 /**
200 * @hot_y: Y coordinate of the cursor hotspot. Used by the legacy cursor
201 * IOCTL when the driver supports cursor through a DRM_PLANE_TYPE_CURSOR
202 * universal plane.
203 */
204 int hot_y;
205 /**
206 * @filp_head: Placed on &drm_file.fbs, protected by &drm_file.fbs_lock.
207 */
208 struct list_head filp_head;
209 /**
210 * @obj: GEM objects backing the framebuffer, one per plane (optional).
211 *
212 * This is used by the GEM framebuffer helpers, see e.g.
213 * drm_gem_fb_create().
214 */
215 struct drm_gem_object *obj[4];
216 };
217
218 #define obj_to_fb(x) container_of(x, struct drm_framebuffer, base)
219
220 int drm_framebuffer_init(struct drm_device *dev,
221 struct drm_framebuffer *fb,
222 const struct drm_framebuffer_funcs *funcs);
223 struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
224 struct drm_file *file_priv,
225 uint32_t id);
226 void drm_framebuffer_remove(struct drm_framebuffer *fb);
227 void drm_framebuffer_cleanup(struct drm_framebuffer *fb);
228 void drm_framebuffer_unregister_private(struct drm_framebuffer *fb);
229
230 /**
231 * drm_framebuffer_get - acquire a framebuffer reference
232 * @fb: DRM framebuffer
233 *
234 * This function increments the framebuffer's reference count.
235 */
drm_framebuffer_get(struct drm_framebuffer * fb)236 static inline void drm_framebuffer_get(struct drm_framebuffer *fb)
237 {
238 drm_mode_object_get(&fb->base);
239 }
240
241 /**
242 * drm_framebuffer_put - release a framebuffer reference
243 * @fb: DRM framebuffer
244 *
245 * This function decrements the framebuffer's reference count and frees the
246 * framebuffer if the reference count drops to zero.
247 */
drm_framebuffer_put(struct drm_framebuffer * fb)248 static inline void drm_framebuffer_put(struct drm_framebuffer *fb)
249 {
250 drm_mode_object_put(&fb->base);
251 }
252
253 /**
254 * drm_framebuffer_read_refcount - read the framebuffer reference count.
255 * @fb: framebuffer
256 *
257 * This functions returns the framebuffer's reference count.
258 */
drm_framebuffer_read_refcount(const struct drm_framebuffer * fb)259 static inline uint32_t drm_framebuffer_read_refcount(const struct drm_framebuffer *fb)
260 {
261 return kref_read(&fb->base.refcount);
262 }
263
264 /**
265 * drm_framebuffer_assign - store a reference to the fb
266 * @p: location to store framebuffer
267 * @fb: new framebuffer (maybe NULL)
268 *
269 * This functions sets the location to store a reference to the framebuffer,
270 * unreferencing the framebuffer that was previously stored in that location.
271 */
drm_framebuffer_assign(struct drm_framebuffer ** p,struct drm_framebuffer * fb)272 static inline void drm_framebuffer_assign(struct drm_framebuffer **p,
273 struct drm_framebuffer *fb)
274 {
275 if (fb)
276 drm_framebuffer_get(fb);
277 if (*p)
278 drm_framebuffer_put(*p);
279 *p = fb;
280 }
281
282 /*
283 * drm_for_each_fb - iterate over all framebuffers
284 * @fb: the loop cursor
285 * @dev: the DRM device
286 *
287 * Iterate over all framebuffers of @dev. User must hold
288 * &drm_mode_config.fb_lock.
289 */
290 #define drm_for_each_fb(fb, dev) \
291 for (WARN_ON(!mutex_is_locked(&(dev)->mode_config.fb_lock)), \
292 fb = list_first_entry(&(dev)->mode_config.fb_list, \
293 struct drm_framebuffer, head); \
294 &fb->head != (&(dev)->mode_config.fb_list); \
295 fb = list_next_entry(fb, head))
296
297 int drm_framebuffer_plane_width(int width,
298 const struct drm_framebuffer *fb, int plane);
299 int drm_framebuffer_plane_height(int height,
300 const struct drm_framebuffer *fb, int plane);
301
302 #endif
303